Brush holder



April 3, 1962 R. A. CHEETHAM 3,028,515

BRUSH HOLDER Filed Oct. 27, 1958 2 sheets sheet 1 kg 24 4s 46 g 2 2 32=2 so Fig.2

INVENTOR.

Roben A. Cheer/ram His: Attorney April 3, 1962 R. A. CHEETHAM BRUSHHOLDER 2 Sheets-Sheet 2 Filed Oct. 27, 1958 m? wwJ 8H J F if QE E W E KQWS 6 86 1@ lG 0m m mm m mm mm mm m INVENTOR. Robert A. Cheer/7am HisAfforryey United States Patent "ice 3,028,515 BRUSH HOLDER Robert A.Cheetham, Anderson, Ind., assignor to General Motors Corporation,Detroit, Mich, a corporation of Delaware Filed Oct. 27, 1958, Ser. No.769,766 2 Claims. (Cl. 310-247) This invention relates to brush riggingfor dynamoelectric machines and more particularly to a brush holder thatis formed from a single piece of sheet metal.

In the past, it has been common practice to form brush holders bywelding, riveting, or otherwise securing sheet metal parts together inthe form of a brush holder. Although these brush holders have operatedsatisfactorily, they have disadvantages in that the welded or rivetedjoint must be made with care so as to avoid failure during use and aremore costly as compared to the brushholder of this invention because ofthe extra assembly steps required.

It is accordingly, an object of this invention to provide a brush holderthat is formed from a single piece of sheet metal. The brush holderpreferably includes a pair of U-shaped members which are integral with abase member and which form a brushholding chamber. By the use of a pairof U-shaped members extending from a base member, the cost offabrication of the brush holder is greatly reduced and the brushholderhas inherent resiliency so as to provide a simple and eifective methodof slidably supporting a brush.

Another object of this invention is to provide a brush holder that isformed with ventilating openings for permitting air to pass in contactwith the brush and wherein at least one of these openings receives alead Wire that is connected with the brush.

Still another object of this invention is to provide a brush holderwhich is formed to achieve line contact between the brush holder andbrush whereby the brush is firmly gripped for sliding movement withoutbinding.

Another object of this invention is to provide a continuous method forforming brush holders from a length of sheet metal.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is a plan view with parts broken away of a dynamoelectricmachine that is fitted with a brush holder of this invention.

FIGURE 2 is a sectional view taken along line 2-2 of FIGURE 1.

FIGURE 3 is a perspective view'of the brush holder of this inventionshowing its relationship with the spring and brush that fit Within thebrush holder.

FIGURE 4 is a plan view illustrating the steps of fabrication of a brushholder made in accordance with this invention. I

FIGURE 5 is a sectional view of apparatus for shaping the length ofsheet metal illustrated in FIGURE 4.

Referring now to the drawings and more particularly to FIGURE 1, adynamoelectric machine generally designated by reference numeral has amain frame 12 connected with end frames 14 and 16 by one or more throughbolts 18. The dynamoelectric machine may be of any conventional designthat includes acommutator 20 supported by a shaft that is journalled forrotation, in the end frames 14 and 16. The shaft carries the usualarmature which rotates within the usual field winding. This particularbrush holder is adapted for use with any type of dynamoelectric machineand the particular con- 3,028,515 Patented Apr. 3, 1962 struction of thedynamoelectric machine therefore forms no part of this invention. Thebrush holder has particular utility, however, in machines that have anannular main frame as the brush holder is attached directly to theannular frame. The dynamoelectric machine has an annular frame 12 towhich is attached the brush holder of this invention. The brush holderin FIGURE 1 is generally designated by reference numeral 22 and issecured to the annular frame 12by means of a fastener 34 which in thiscase is a rivet. The brush holder is insulated from the frame byinsulating material 26 and 28 as is better shown in FIGURE 2. The brushholder contains a brush of any well known construction 30 which slideswithin the brush holder and which is spring biased against thecommutator by a spring 32. One end of the spring encircles the head 34of the rivet and the rivet head thus serves to position the springwithin the brush holder. The brush holder of this invention is formedfrom a single piece of sheet metal material. The brush holder as is bestillustrated in FIGURE 3 has an arcuately extending base portion 24 whichis adapted to fit the annular main frame of the dynamoelectric machine.The base portion 24 has an aperture 36 which receives the fastener 34when the brush holder is being secured to the annular frame of thedynamoelectric machine. EX- tending radially from the arcuatelyextending base portion 24 are a pair of U-shaped members 38 and 40 as isbest illustrated in FIGURE 3. Each U-shaped member has an outwardlyflared edge 42 and has an arcuately extending web portion 44. The loweredges of the U-shaped members are spaced from the base member 24 toprovide ventilating passages designated by reference numeral 4-6.

The U-shaped members have their open ends facing one another to formventilating passages 48, one of which also serves to receive the leadwire 50 of the brush. The lead wire will of course be connected witheither the field winding of the dynamoelectric machine or directly tothe frame, depending upon whether the brush is insulated from the frameor Whether it is connected directly to the frame. The connection of thebrush to the dynamoelectric machine will of course vary with the type ofmachine with which the brush holder is being used.

It will be apparent from an inspection of FIGURE 3 that the brush holder22 provides for a firm gripping of the brush 30 when it is insertedwithin the brush holder. Thus, the arcuate portions 44 of the brushholder serve to effect a line contact with the edges of the brush whilethe side walls 52 of the U-shaped members operate to engage the sidefaces of the brush without causing binding. The inherent resiliency ofthe brush-holder due to its formation from a single piece of sheet metalalso operates to provide a brush holder that engages the brush withoutany binding as the brush holder is free to give in certain directions.Thus the Ushaped members are free to move away from one another a smallamount due to the inherent resiliency of the brush holder and also theside walls 52 are free to'move away from one another due to the inherentresiliency of the sheet metal brush holder.

In FIGURES 4 and 5 a preferred method for forming the brush holder 22 isshown. The apparatus for forming the brush holder includes a platemember 60 which may be reciprocated by a punch press or the like notshown and a die holding member 62. The member 60 carries punches 64, 66,68, 7t} and 72 which operate to form various operations on a length ofsheet metal designated by reference numeral 74. The die holder supportsdies 76, 78 83 and 8-5. The sheet metal member 74 is fed between members60 and 62 by a suitable feeder mechanism not shown that preferablyoperates in' synchronism with the punch press or other device thatreciprocates plate 6%. As the sheet metal piece 74 is fed between theplates dti'and 62, several shaping and forming operations are performedon the length of sheet metal. The first operation performed starting atthe right hand side of the FIGURE is the punching out of apertures 36.These apertures are punched out by the punch member 64. Simultaneouslywith the punching out of apertures 36, the apertures 84} are formed bysuitable punches not shown. The apertures 82 are also simultaneouslyformed-bysuitable punches not shown during the time that the apertures36 are formed. As the material 74 moves through the punch press, a pairof tools '66 operate to form the apertures 84; When apertures 80 and 84have been formed, the-sheetmetal has a generally cross-shape provided bysections 86 and sections 37 and 3?. Following the formation of apertures8 the sections 86 are placed between die members 76 and punch 68 to formthe outwardly flared portion 420i the'brush I holder and to also formthe arcuately extending web portion 44; Foiiowing this operation thesections 86 are fed between punch 7t) and dies 78'and- 83 to fornr ly totheir final position by upward extensions of die member 83 not shownwhich have an outer configuration that corresponds to the outerconfiguration of the U- shaped members after they have'been pressedbetweenpunch 70 and die members 78 and 83.- These two upward extensionsthus force the U-shaped members toward one another during the ,time'thatthe tool'or punch 70 is being forced downwardly. The" final end productis'illustrated in FIGURE 3 of the drawings and has been fully describedj hereinbefore'.

It will be appreciated that the method for forming these brush holdersis continuous as the material is con- 'tinuously fed between plates 68and 6 2. The plate constantly reciprocates to simultaneously perform allthe operations described above once the material has been :fed entirelythrough the punch press.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. A brush holder for a dynamoelectric machine formed from a singlepiece of sheet metal oomprising, an arouately extending base portion, apair of spaced U- shaped members integral with and extending from saidbase portion and facing each other to form a brush holding chamber, eachU shaped member having a pair of'side walls joined'by an arcuatelyextending web, said side walls terminatingin an outwardly flared edgeand having ends located adjacent to and spaced from said arcuatelyextending base portion.

2. In combination with a dynamoelectric machine having an annular frameand a commutator, a brush holder 7 having an arcuately extendingbase'portion secured, to said frame,-a pair ofspaced U-shaped membersintegralwith and extending from said base portion and facing each" otherto form a rectangular-shapedbrush holding'chamber, each U-shaped memberbeing defined'by a pair of side walls that are joined by an arcuatelyextending web, a brush slidable in said brush holding chamber having endwalls that are in line contact with said arcuately 6X' tending webs, anda spring interposed between said arcu-' ately extending base portion andsaid brush for urging said brush into engagement with said commutator.

References Cited in the file of this patent UNITED STATES PATENTS1,101,814 Sammarone June 30, 1914 1,519,222 Seiss Dec. 16, 19242,825,831 Franck Mar. 4, 1958 2,870,354 Antonidis Jan. 20, 19 59 FOREIGNPATENTS v 243,204 Switzerland Dec. 2, 1946'

